1. Field of the Invention
The present invention relates to a data path for a maskless lithography apparatus, and in particular to a data path for transferring pattern data for control of a plurality of charged particle beamlets.
2. Description of the Related Art
A design for an integrated circuit is typically represented in a computer-readable file containing data for patterning each layer of the integrated circuit onto a silicon wafer. For lithography machines which use masks, this pattern data is typically used to manufacture a mask or set of masks which are then used by the lithography machine for patterning the wafer. For maskless lithography machines, the pattern data file is electronically processed to put it into a format suitable for controlling the lithography machine. For charged particle lithography machines, the pattern data file is converted into a set of data signals for controlling the charged particle beams used in the lithography process.
A maskless lithography machine using charged particles to expose the wafer may use a very large number of charged particle beams to produce the desired patterning critical dimensions while achieving the required throughput. A data path is typically used to transmit the pattern data from an off-line data processing and storage system to the lithography machine. A very large quantity of data is required to represent the pattern for the current and near future generations of integrated circuit, necessitating a data path having a very large number of channels and very high data transmission rates per channel. However, this greatly increases the cost of the data path and it becomes a major component of the overall cost of a charged particle lithography machine. Due to the very large number of charged particle beams and data path channels, it is likely that a portion of the data path channels and components for generating and modulating the charged particle beams will suffer a failure or degradation in performance and should be not be used.